A fluorometric method for mercury(II) detection based on the use of pyrophosphate-modified carbon quantum dots

Pyrophosphate-modified carbon quantum dots (PP-CDs) are demonstrated to be a viable fluorescent nanoprobe for mercury(II) (Hg2+) detection. Hg2+ reacts with the pyrophosphate groups on the surface of PP-CDs to form a non-fluorescent complex. This results in quenching of the green fluorescence which has excitation/emission peaks at 400/513 nm. Static quenching is shown to be the dominant mechanism. The probe works in 0.1 μM to 1.4 μM Hg2+ concentration range, and the limit of detection is 2 nM. The PP-CDs were also used to visualize Hg2+ inside human hepatocyte LO2 cells.